1// SPDX-License-Identifier: GPL-2.0 2/* 3 * Kprobes-based tracing events 4 * 5 * Created by Masami Hiramatsu <mhiramat@redhat.com> 6 * 7 */ 8#define pr_fmt(fmt) "trace_kprobe: " fmt 9 10#include <linux/bpf-cgroup.h> 11#include <linux/security.h> 12#include <linux/module.h> 13#include <linux/uaccess.h> 14#include <linux/rculist.h> 15#include <linux/error-injection.h> 16 17#include <asm/setup.h> /* for COMMAND_LINE_SIZE */ 18 19#include "trace_dynevent.h" 20#include "trace_kprobe_selftest.h" 21#include "trace_probe.h" 22#include "trace_probe_tmpl.h" 23#include "trace_probe_kernel.h" 24 25#define KPROBE_EVENT_SYSTEM "kprobes" 26#define KRETPROBE_MAXACTIVE_MAX 4096 27 28/* Kprobe early definition from command line */ 29static char kprobe_boot_events_buf[COMMAND_LINE_SIZE] __initdata; 30 31static int __init set_kprobe_boot_events(char *str) 32{ 33 strscpy(kprobe_boot_events_buf, str, COMMAND_LINE_SIZE); 34 disable_tracing_selftest("running kprobe events"); 35 36 return 1; 37} 38__setup("kprobe_event=", set_kprobe_boot_events); 39 40static int trace_kprobe_create(const char *raw_command); 41static int trace_kprobe_show(struct seq_file *m, struct dyn_event *ev); 42static int trace_kprobe_release(struct dyn_event *ev); 43static bool trace_kprobe_is_busy(struct dyn_event *ev); 44static bool trace_kprobe_match(const char *system, const char *event, 45 int argc, const char **argv, struct dyn_event *ev); 46 47static struct dyn_event_operations trace_kprobe_ops = { 48 .create = trace_kprobe_create, 49 .show = trace_kprobe_show, 50 .is_busy = trace_kprobe_is_busy, 51 .free = trace_kprobe_release, 52 .match = trace_kprobe_match, 53}; 54 55/* 56 * Kprobe event core functions 57 */ 58struct trace_kprobe { 59 struct dyn_event devent; 60 struct kretprobe rp; /* Use rp.kp for kprobe use */ 61 unsigned long __percpu *nhit; 62 const char *symbol; /* symbol name */ 63 struct trace_probe tp; 64}; 65 66static bool is_trace_kprobe(struct dyn_event *ev) 67{ 68 return ev->ops == &trace_kprobe_ops; 69} 70 71static struct trace_kprobe *to_trace_kprobe(struct dyn_event *ev) 72{ 73 return container_of(ev, struct trace_kprobe, devent); 74} 75 76/** 77 * for_each_trace_kprobe - iterate over the trace_kprobe list 78 * @pos: the struct trace_kprobe * for each entry 79 * @dpos: the struct dyn_event * to use as a loop cursor 80 */ 81#define for_each_trace_kprobe(pos, dpos) \ 82 for_each_dyn_event(dpos) \ 83 if (is_trace_kprobe(dpos) && (pos = to_trace_kprobe(dpos))) 84 85static nokprobe_inline bool trace_kprobe_is_return(struct trace_kprobe *tk) 86{ 87 return tk->rp.handler != NULL; 88} 89 90static nokprobe_inline const char *trace_kprobe_symbol(struct trace_kprobe *tk) 91{ 92 return tk->symbol ? tk->symbol : "unknown"; 93} 94 95static nokprobe_inline unsigned long trace_kprobe_offset(struct trace_kprobe *tk) 96{ 97 return tk->rp.kp.offset; 98} 99 100static nokprobe_inline bool trace_kprobe_has_gone(struct trace_kprobe *tk) 101{ 102 return kprobe_gone(&tk->rp.kp); 103} 104 105static nokprobe_inline bool trace_kprobe_within_module(struct trace_kprobe *tk, 106 struct module *mod) 107{ 108 int len = strlen(module_name(mod)); 109 const char *name = trace_kprobe_symbol(tk); 110 111 return strncmp(module_name(mod), name, len) == 0 && name[len] == ':'; 112} 113 114static nokprobe_inline bool trace_kprobe_module_exist(struct trace_kprobe *tk) 115{ 116 char *p; 117 bool ret; 118 119 if (!tk->symbol) 120 return false; 121 p = strchr(tk->symbol, ':'); 122 if (!p) 123 return true; 124 *p = '\0'; 125 rcu_read_lock_sched(); 126 ret = !!find_module(tk->symbol); 127 rcu_read_unlock_sched(); 128 *p = ':'; 129 130 return ret; 131} 132 133static bool trace_kprobe_is_busy(struct dyn_event *ev) 134{ 135 struct trace_kprobe *tk = to_trace_kprobe(ev); 136 137 return trace_probe_is_enabled(&tk->tp); 138} 139 140static bool trace_kprobe_match_command_head(struct trace_kprobe *tk, 141 int argc, const char **argv) 142{ 143 char buf[MAX_ARGSTR_LEN + 1]; 144 145 if (!argc) 146 return true; 147 148 if (!tk->symbol) 149 snprintf(buf, sizeof(buf), "0x%p", tk->rp.kp.addr); 150 else if (tk->rp.kp.offset) 151 snprintf(buf, sizeof(buf), "%s+%u", 152 trace_kprobe_symbol(tk), tk->rp.kp.offset); 153 else 154 snprintf(buf, sizeof(buf), "%s", trace_kprobe_symbol(tk)); 155 if (strcmp(buf, argv[0])) 156 return false; 157 argc--; argv++; 158 159 return trace_probe_match_command_args(&tk->tp, argc, argv); 160} 161 162static bool trace_kprobe_match(const char *system, const char *event, 163 int argc, const char **argv, struct dyn_event *ev) 164{ 165 struct trace_kprobe *tk = to_trace_kprobe(ev); 166 167 return (event[0] == '\0' || 168 strcmp(trace_probe_name(&tk->tp), event) == 0) && 169 (!system || strcmp(trace_probe_group_name(&tk->tp), system) == 0) && 170 trace_kprobe_match_command_head(tk, argc, argv); 171} 172 173static nokprobe_inline unsigned long trace_kprobe_nhit(struct trace_kprobe *tk) 174{ 175 unsigned long nhit = 0; 176 int cpu; 177 178 for_each_possible_cpu(cpu) 179 nhit += *per_cpu_ptr(tk->nhit, cpu); 180 181 return nhit; 182} 183 184static nokprobe_inline bool trace_kprobe_is_registered(struct trace_kprobe *tk) 185{ 186 return !(list_empty(&tk->rp.kp.list) && 187 hlist_unhashed(&tk->rp.kp.hlist)); 188} 189 190/* Return 0 if it fails to find the symbol address */ 191static nokprobe_inline 192unsigned long trace_kprobe_address(struct trace_kprobe *tk) 193{ 194 unsigned long addr; 195 196 if (tk->symbol) { 197 addr = (unsigned long) 198 kallsyms_lookup_name(trace_kprobe_symbol(tk)); 199 if (addr) 200 addr += tk->rp.kp.offset; 201 } else { 202 addr = (unsigned long)tk->rp.kp.addr; 203 } 204 return addr; 205} 206 207static nokprobe_inline struct trace_kprobe * 208trace_kprobe_primary_from_call(struct trace_event_call *call) 209{ 210 struct trace_probe *tp; 211 212 tp = trace_probe_primary_from_call(call); 213 if (WARN_ON_ONCE(!tp)) 214 return NULL; 215 216 return container_of(tp, struct trace_kprobe, tp); 217} 218 219bool trace_kprobe_on_func_entry(struct trace_event_call *call) 220{ 221 struct trace_kprobe *tk = trace_kprobe_primary_from_call(call); 222 223 return tk ? (kprobe_on_func_entry(tk->rp.kp.addr, 224 tk->rp.kp.addr ? NULL : tk->rp.kp.symbol_name, 225 tk->rp.kp.addr ? 0 : tk->rp.kp.offset) == 0) : false; 226} 227 228bool trace_kprobe_error_injectable(struct trace_event_call *call) 229{ 230 struct trace_kprobe *tk = trace_kprobe_primary_from_call(call); 231 232 return tk ? within_error_injection_list(trace_kprobe_address(tk)) : 233 false; 234} 235 236static int register_kprobe_event(struct trace_kprobe *tk); 237static int unregister_kprobe_event(struct trace_kprobe *tk); 238 239static int kprobe_dispatcher(struct kprobe *kp, struct pt_regs *regs); 240static int kretprobe_dispatcher(struct kretprobe_instance *ri, 241 struct pt_regs *regs); 242 243static void free_trace_kprobe(struct trace_kprobe *tk) 244{ 245 if (tk) { 246 trace_probe_cleanup(&tk->tp); 247 kfree(tk->symbol); 248 free_percpu(tk->nhit); 249 kfree(tk); 250 } 251} 252 253/* 254 * Allocate new trace_probe and initialize it (including kprobes). 255 */ 256static struct trace_kprobe *alloc_trace_kprobe(const char *group, 257 const char *event, 258 void *addr, 259 const char *symbol, 260 unsigned long offs, 261 int maxactive, 262 int nargs, bool is_return) 263{ 264 struct trace_kprobe *tk; 265 int ret = -ENOMEM; 266 267 tk = kzalloc(struct_size(tk, tp.args, nargs), GFP_KERNEL); 268 if (!tk) 269 return ERR_PTR(ret); 270 271 tk->nhit = alloc_percpu(unsigned long); 272 if (!tk->nhit) 273 goto error; 274 275 if (symbol) { 276 tk->symbol = kstrdup(symbol, GFP_KERNEL); 277 if (!tk->symbol) 278 goto error; 279 tk->rp.kp.symbol_name = tk->symbol; 280 tk->rp.kp.offset = offs; 281 } else 282 tk->rp.kp.addr = addr; 283 284 if (is_return) 285 tk->rp.handler = kretprobe_dispatcher; 286 else 287 tk->rp.kp.pre_handler = kprobe_dispatcher; 288 289 tk->rp.maxactive = maxactive; 290 INIT_HLIST_NODE(&tk->rp.kp.hlist); 291 INIT_LIST_HEAD(&tk->rp.kp.list); 292 293 ret = trace_probe_init(&tk->tp, event, group, false, nargs); 294 if (ret < 0) 295 goto error; 296 297 dyn_event_init(&tk->devent, &trace_kprobe_ops); 298 return tk; 299error: 300 free_trace_kprobe(tk); 301 return ERR_PTR(ret); 302} 303 304static struct trace_kprobe *find_trace_kprobe(const char *event, 305 const char *group) 306{ 307 struct dyn_event *pos; 308 struct trace_kprobe *tk; 309 310 for_each_trace_kprobe(tk, pos) 311 if (strcmp(trace_probe_name(&tk->tp), event) == 0 && 312 strcmp(trace_probe_group_name(&tk->tp), group) == 0) 313 return tk; 314 return NULL; 315} 316 317static inline int __enable_trace_kprobe(struct trace_kprobe *tk) 318{ 319 int ret = 0; 320 321 if (trace_kprobe_is_registered(tk) && !trace_kprobe_has_gone(tk)) { 322 if (trace_kprobe_is_return(tk)) 323 ret = enable_kretprobe(&tk->rp); 324 else 325 ret = enable_kprobe(&tk->rp.kp); 326 } 327 328 return ret; 329} 330 331static void __disable_trace_kprobe(struct trace_probe *tp) 332{ 333 struct trace_kprobe *tk; 334 335 list_for_each_entry(tk, trace_probe_probe_list(tp), tp.list) { 336 if (!trace_kprobe_is_registered(tk)) 337 continue; 338 if (trace_kprobe_is_return(tk)) 339 disable_kretprobe(&tk->rp); 340 else 341 disable_kprobe(&tk->rp.kp); 342 } 343} 344 345/* 346 * Enable trace_probe 347 * if the file is NULL, enable "perf" handler, or enable "trace" handler. 348 */ 349static int enable_trace_kprobe(struct trace_event_call *call, 350 struct trace_event_file *file) 351{ 352 struct trace_probe *tp; 353 struct trace_kprobe *tk; 354 bool enabled; 355 int ret = 0; 356 357 tp = trace_probe_primary_from_call(call); 358 if (WARN_ON_ONCE(!tp)) 359 return -ENODEV; 360 enabled = trace_probe_is_enabled(tp); 361 362 /* This also changes "enabled" state */ 363 if (file) { 364 ret = trace_probe_add_file(tp, file); 365 if (ret) 366 return ret; 367 } else 368 trace_probe_set_flag(tp, TP_FLAG_PROFILE); 369 370 if (enabled) 371 return 0; 372 373 list_for_each_entry(tk, trace_probe_probe_list(tp), tp.list) { 374 if (trace_kprobe_has_gone(tk)) 375 continue; 376 ret = __enable_trace_kprobe(tk); 377 if (ret) 378 break; 379 enabled = true; 380 } 381 382 if (ret) { 383 /* Failed to enable one of them. Roll back all */ 384 if (enabled) 385 __disable_trace_kprobe(tp); 386 if (file) 387 trace_probe_remove_file(tp, file); 388 else 389 trace_probe_clear_flag(tp, TP_FLAG_PROFILE); 390 } 391 392 return ret; 393} 394 395/* 396 * Disable trace_probe 397 * if the file is NULL, disable "perf" handler, or disable "trace" handler. 398 */ 399static int disable_trace_kprobe(struct trace_event_call *call, 400 struct trace_event_file *file) 401{ 402 struct trace_probe *tp; 403 404 tp = trace_probe_primary_from_call(call); 405 if (WARN_ON_ONCE(!tp)) 406 return -ENODEV; 407 408 if (file) { 409 if (!trace_probe_get_file_link(tp, file)) 410 return -ENOENT; 411 if (!trace_probe_has_single_file(tp)) 412 goto out; 413 trace_probe_clear_flag(tp, TP_FLAG_TRACE); 414 } else 415 trace_probe_clear_flag(tp, TP_FLAG_PROFILE); 416 417 if (!trace_probe_is_enabled(tp)) 418 __disable_trace_kprobe(tp); 419 420 out: 421 if (file) 422 /* 423 * Synchronization is done in below function. For perf event, 424 * file == NULL and perf_trace_event_unreg() calls 425 * tracepoint_synchronize_unregister() to ensure synchronize 426 * event. We don't need to care about it. 427 */ 428 trace_probe_remove_file(tp, file); 429 430 return 0; 431} 432 433#if defined(CONFIG_DYNAMIC_FTRACE) && \ 434 !defined(CONFIG_KPROBE_EVENTS_ON_NOTRACE) 435static bool __within_notrace_func(unsigned long addr) 436{ 437 unsigned long offset, size; 438 439 if (!addr || !kallsyms_lookup_size_offset(addr, &size, &offset)) 440 return false; 441 442 /* Get the entry address of the target function */ 443 addr -= offset; 444 445 /* 446 * Since ftrace_location_range() does inclusive range check, we need 447 * to subtract 1 byte from the end address. 448 */ 449 return !ftrace_location_range(addr, addr + size - 1); 450} 451 452static bool within_notrace_func(struct trace_kprobe *tk) 453{ 454 unsigned long addr = trace_kprobe_address(tk); 455 char symname[KSYM_NAME_LEN], *p; 456 457 if (!__within_notrace_func(addr)) 458 return false; 459 460 /* Check if the address is on a suffixed-symbol */ 461 if (!lookup_symbol_name(addr, symname)) { 462 p = strchr(symname, '.'); 463 if (!p) 464 return true; 465 *p = '\0'; 466 addr = (unsigned long)kprobe_lookup_name(symname, 0); 467 if (addr) 468 return __within_notrace_func(addr); 469 } 470 471 return true; 472} 473#else 474#define within_notrace_func(tk) (false) 475#endif 476 477/* Internal register function - just handle k*probes and flags */ 478static int __register_trace_kprobe(struct trace_kprobe *tk) 479{ 480 int i, ret; 481 482 ret = security_locked_down(LOCKDOWN_KPROBES); 483 if (ret) 484 return ret; 485 486 if (trace_kprobe_is_registered(tk)) 487 return -EINVAL; 488 489 if (within_notrace_func(tk)) { 490 pr_warn("Could not probe notrace function %ps\n", 491 (void *)trace_kprobe_address(tk)); 492 return -EINVAL; 493 } 494 495 for (i = 0; i < tk->tp.nr_args; i++) { 496 ret = traceprobe_update_arg(&tk->tp.args[i]); 497 if (ret) 498 return ret; 499 } 500 501 /* Set/clear disabled flag according to tp->flag */ 502 if (trace_probe_is_enabled(&tk->tp)) 503 tk->rp.kp.flags &= ~KPROBE_FLAG_DISABLED; 504 else 505 tk->rp.kp.flags |= KPROBE_FLAG_DISABLED; 506 507 if (trace_kprobe_is_return(tk)) 508 ret = register_kretprobe(&tk->rp); 509 else 510 ret = register_kprobe(&tk->rp.kp); 511 512 return ret; 513} 514 515/* Internal unregister function - just handle k*probes and flags */ 516static void __unregister_trace_kprobe(struct trace_kprobe *tk) 517{ 518 if (trace_kprobe_is_registered(tk)) { 519 if (trace_kprobe_is_return(tk)) 520 unregister_kretprobe(&tk->rp); 521 else 522 unregister_kprobe(&tk->rp.kp); 523 /* Cleanup kprobe for reuse and mark it unregistered */ 524 INIT_HLIST_NODE(&tk->rp.kp.hlist); 525 INIT_LIST_HEAD(&tk->rp.kp.list); 526 if (tk->rp.kp.symbol_name) 527 tk->rp.kp.addr = NULL; 528 } 529} 530 531/* Unregister a trace_probe and probe_event */ 532static int unregister_trace_kprobe(struct trace_kprobe *tk) 533{ 534 /* If other probes are on the event, just unregister kprobe */ 535 if (trace_probe_has_sibling(&tk->tp)) 536 goto unreg; 537 538 /* Enabled event can not be unregistered */ 539 if (trace_probe_is_enabled(&tk->tp)) 540 return -EBUSY; 541 542 /* If there's a reference to the dynamic event */ 543 if (trace_event_dyn_busy(trace_probe_event_call(&tk->tp))) 544 return -EBUSY; 545 546 /* Will fail if probe is being used by ftrace or perf */ 547 if (unregister_kprobe_event(tk)) 548 return -EBUSY; 549 550unreg: 551 __unregister_trace_kprobe(tk); 552 dyn_event_remove(&tk->devent); 553 trace_probe_unlink(&tk->tp); 554 555 return 0; 556} 557 558static bool trace_kprobe_has_same_kprobe(struct trace_kprobe *orig, 559 struct trace_kprobe *comp) 560{ 561 struct trace_probe_event *tpe = orig->tp.event; 562 int i; 563 564 list_for_each_entry(orig, &tpe->probes, tp.list) { 565 if (strcmp(trace_kprobe_symbol(orig), 566 trace_kprobe_symbol(comp)) || 567 trace_kprobe_offset(orig) != trace_kprobe_offset(comp)) 568 continue; 569 570 /* 571 * trace_probe_compare_arg_type() ensured that nr_args and 572 * each argument name and type are same. Let's compare comm. 573 */ 574 for (i = 0; i < orig->tp.nr_args; i++) { 575 if (strcmp(orig->tp.args[i].comm, 576 comp->tp.args[i].comm)) 577 break; 578 } 579 580 if (i == orig->tp.nr_args) 581 return true; 582 } 583 584 return false; 585} 586 587static int append_trace_kprobe(struct trace_kprobe *tk, struct trace_kprobe *to) 588{ 589 int ret; 590 591 ret = trace_probe_compare_arg_type(&tk->tp, &to->tp); 592 if (ret) { 593 /* Note that argument starts index = 2 */ 594 trace_probe_log_set_index(ret + 1); 595 trace_probe_log_err(0, DIFF_ARG_TYPE); 596 return -EEXIST; 597 } 598 if (trace_kprobe_has_same_kprobe(to, tk)) { 599 trace_probe_log_set_index(0); 600 trace_probe_log_err(0, SAME_PROBE); 601 return -EEXIST; 602 } 603 604 /* Append to existing event */ 605 ret = trace_probe_append(&tk->tp, &to->tp); 606 if (ret) 607 return ret; 608 609 /* Register k*probe */ 610 ret = __register_trace_kprobe(tk); 611 if (ret == -ENOENT && !trace_kprobe_module_exist(tk)) { 612 pr_warn("This probe might be able to register after target module is loaded. Continue.\n"); 613 ret = 0; 614 } 615 616 if (ret) 617 trace_probe_unlink(&tk->tp); 618 else 619 dyn_event_add(&tk->devent, trace_probe_event_call(&tk->tp)); 620 621 return ret; 622} 623 624/* Register a trace_probe and probe_event */ 625static int register_trace_kprobe(struct trace_kprobe *tk) 626{ 627 struct trace_kprobe *old_tk; 628 int ret; 629 630 mutex_lock(&event_mutex); 631 632 old_tk = find_trace_kprobe(trace_probe_name(&tk->tp), 633 trace_probe_group_name(&tk->tp)); 634 if (old_tk) { 635 if (trace_kprobe_is_return(tk) != trace_kprobe_is_return(old_tk)) { 636 trace_probe_log_set_index(0); 637 trace_probe_log_err(0, DIFF_PROBE_TYPE); 638 ret = -EEXIST; 639 } else { 640 ret = append_trace_kprobe(tk, old_tk); 641 } 642 goto end; 643 } 644 645 /* Register new event */ 646 ret = register_kprobe_event(tk); 647 if (ret) { 648 if (ret == -EEXIST) { 649 trace_probe_log_set_index(0); 650 trace_probe_log_err(0, EVENT_EXIST); 651 } else 652 pr_warn("Failed to register probe event(%d)\n", ret); 653 goto end; 654 } 655 656 /* Register k*probe */ 657 ret = __register_trace_kprobe(tk); 658 if (ret == -ENOENT && !trace_kprobe_module_exist(tk)) { 659 pr_warn("This probe might be able to register after target module is loaded. Continue.\n"); 660 ret = 0; 661 } 662 663 if (ret < 0) 664 unregister_kprobe_event(tk); 665 else 666 dyn_event_add(&tk->devent, trace_probe_event_call(&tk->tp)); 667 668end: 669 mutex_unlock(&event_mutex); 670 return ret; 671} 672 673/* Module notifier call back, checking event on the module */ 674static int trace_kprobe_module_callback(struct notifier_block *nb, 675 unsigned long val, void *data) 676{ 677 struct module *mod = data; 678 struct dyn_event *pos; 679 struct trace_kprobe *tk; 680 int ret; 681 682 if (val != MODULE_STATE_COMING) 683 return NOTIFY_DONE; 684 685 /* Update probes on coming module */ 686 mutex_lock(&event_mutex); 687 for_each_trace_kprobe(tk, pos) { 688 if (trace_kprobe_within_module(tk, mod)) { 689 /* Don't need to check busy - this should have gone. */ 690 __unregister_trace_kprobe(tk); 691 ret = __register_trace_kprobe(tk); 692 if (ret) 693 pr_warn("Failed to re-register probe %s on %s: %d\n", 694 trace_probe_name(&tk->tp), 695 module_name(mod), ret); 696 } 697 } 698 mutex_unlock(&event_mutex); 699 700 return NOTIFY_DONE; 701} 702 703static struct notifier_block trace_kprobe_module_nb = { 704 .notifier_call = trace_kprobe_module_callback, 705 .priority = 1 /* Invoked after kprobe module callback */ 706}; 707 708static int count_symbols(void *data, unsigned long unused) 709{ 710 unsigned int *count = data; 711 712 (*count)++; 713 714 return 0; 715} 716 717struct sym_count_ctx { 718 unsigned int count; 719 const char *name; 720}; 721 722static int count_mod_symbols(void *data, const char *name, unsigned long unused) 723{ 724 struct sym_count_ctx *ctx = data; 725 726 if (strcmp(name, ctx->name) == 0) 727 ctx->count++; 728 729 return 0; 730} 731 732static unsigned int number_of_same_symbols(char *func_name) 733{ 734 struct sym_count_ctx ctx = { .count = 0, .name = func_name }; 735 736 kallsyms_on_each_match_symbol(count_symbols, func_name, &ctx.count); 737 738 module_kallsyms_on_each_symbol(NULL, count_mod_symbols, &ctx); 739 740 return ctx.count; 741} 742 743static int trace_kprobe_entry_handler(struct kretprobe_instance *ri, 744 struct pt_regs *regs); 745 746static int __trace_kprobe_create(int argc, const char *argv[]) 747{ 748 /* 749 * Argument syntax: 750 * - Add kprobe: 751 * p[:[GRP/][EVENT]] [MOD:]KSYM[+OFFS]|KADDR [FETCHARGS] 752 * - Add kretprobe: 753 * r[MAXACTIVE][:[GRP/][EVENT]] [MOD:]KSYM[+0] [FETCHARGS] 754 * Or 755 * p[:[GRP/][EVENT]] [MOD:]KSYM[+0]%return [FETCHARGS] 756 * 757 * Fetch args: 758 * $retval : fetch return value 759 * $stack : fetch stack address 760 * $stackN : fetch Nth of stack (N:0-) 761 * $comm : fetch current task comm 762 * @ADDR : fetch memory at ADDR (ADDR should be in kernel) 763 * @SYM[+|-offs] : fetch memory at SYM +|- offs (SYM is a data symbol) 764 * %REG : fetch register REG 765 * Dereferencing memory fetch: 766 * +|-offs(ARG) : fetch memory at ARG +|- offs address. 767 * Alias name of args: 768 * NAME=FETCHARG : set NAME as alias of FETCHARG. 769 * Type of args: 770 * FETCHARG:TYPE : use TYPE instead of unsigned long. 771 */ 772 struct trace_kprobe *tk = NULL; 773 int i, len, new_argc = 0, ret = 0; 774 bool is_return = false; 775 char *symbol = NULL, *tmp = NULL; 776 const char **new_argv = NULL; 777 const char *event = NULL, *group = KPROBE_EVENT_SYSTEM; 778 enum probe_print_type ptype; 779 int maxactive = 0; 780 long offset = 0; 781 void *addr = NULL; 782 char buf[MAX_EVENT_NAME_LEN]; 783 char gbuf[MAX_EVENT_NAME_LEN]; 784 char abuf[MAX_BTF_ARGS_LEN]; 785 struct traceprobe_parse_context ctx = { .flags = TPARG_FL_KERNEL }; 786 787 switch (argv[0][0]) { 788 case 'r': 789 is_return = true; 790 break; 791 case 'p': 792 break; 793 default: 794 return -ECANCELED; 795 } 796 if (argc < 2) 797 return -ECANCELED; 798 799 trace_probe_log_init("trace_kprobe", argc, argv); 800 801 event = strchr(&argv[0][1], ':'); 802 if (event) 803 event++; 804 805 if (isdigit(argv[0][1])) { 806 if (!is_return) { 807 trace_probe_log_err(1, BAD_MAXACT_TYPE); 808 goto parse_error; 809 } 810 if (event) 811 len = event - &argv[0][1] - 1; 812 else 813 len = strlen(&argv[0][1]); 814 if (len > MAX_EVENT_NAME_LEN - 1) { 815 trace_probe_log_err(1, BAD_MAXACT); 816 goto parse_error; 817 } 818 memcpy(buf, &argv[0][1], len); 819 buf[len] = '\0'; 820 ret = kstrtouint(buf, 0, &maxactive); 821 if (ret || !maxactive) { 822 trace_probe_log_err(1, BAD_MAXACT); 823 goto parse_error; 824 } 825 /* kretprobes instances are iterated over via a list. The 826 * maximum should stay reasonable. 827 */ 828 if (maxactive > KRETPROBE_MAXACTIVE_MAX) { 829 trace_probe_log_err(1, MAXACT_TOO_BIG); 830 goto parse_error; 831 } 832 } 833 834 /* try to parse an address. if that fails, try to read the 835 * input as a symbol. */ 836 if (kstrtoul(argv[1], 0, (unsigned long *)&addr)) { 837 trace_probe_log_set_index(1); 838 /* Check whether uprobe event specified */ 839 if (strchr(argv[1], '/') && strchr(argv[1], ':')) { 840 ret = -ECANCELED; 841 goto error; 842 } 843 /* a symbol specified */ 844 symbol = kstrdup(argv[1], GFP_KERNEL); 845 if (!symbol) 846 return -ENOMEM; 847 848 tmp = strchr(symbol, '%'); 849 if (tmp) { 850 if (!strcmp(tmp, "%return")) { 851 *tmp = '\0'; 852 is_return = true; 853 } else { 854 trace_probe_log_err(tmp - symbol, BAD_ADDR_SUFFIX); 855 goto parse_error; 856 } 857 } 858 859 /* TODO: support .init module functions */ 860 ret = traceprobe_split_symbol_offset(symbol, &offset); 861 if (ret || offset < 0 || offset > UINT_MAX) { 862 trace_probe_log_err(0, BAD_PROBE_ADDR); 863 goto parse_error; 864 } 865 if (is_return) 866 ctx.flags |= TPARG_FL_RETURN; 867 ret = kprobe_on_func_entry(NULL, symbol, offset); 868 if (ret == 0 && !is_return) 869 ctx.flags |= TPARG_FL_FENTRY; 870 /* Defer the ENOENT case until register kprobe */ 871 if (ret == -EINVAL && is_return) { 872 trace_probe_log_err(0, BAD_RETPROBE); 873 goto parse_error; 874 } 875 } 876 877 if (symbol && !strchr(symbol, ':')) { 878 unsigned int count; 879 880 count = number_of_same_symbols(symbol); 881 if (count > 1) { 882 /* 883 * Users should use ADDR to remove the ambiguity of 884 * using KSYM only. 885 */ 886 trace_probe_log_err(0, NON_UNIQ_SYMBOL); 887 ret = -EADDRNOTAVAIL; 888 889 goto error; 890 } else if (count == 0) { 891 /* 892 * We can return ENOENT earlier than when register the 893 * kprobe. 894 */ 895 trace_probe_log_err(0, BAD_PROBE_ADDR); 896 ret = -ENOENT; 897 898 goto error; 899 } 900 } 901 902 trace_probe_log_set_index(0); 903 if (event) { 904 ret = traceprobe_parse_event_name(&event, &group, gbuf, 905 event - argv[0]); 906 if (ret) 907 goto parse_error; 908 } 909 910 if (!event) { 911 /* Make a new event name */ 912 if (symbol) 913 snprintf(buf, MAX_EVENT_NAME_LEN, "%c_%s_%ld", 914 is_return ? 'r' : 'p', symbol, offset); 915 else 916 snprintf(buf, MAX_EVENT_NAME_LEN, "%c_0x%p", 917 is_return ? 'r' : 'p', addr); 918 sanitize_event_name(buf); 919 event = buf; 920 } 921 922 argc -= 2; argv += 2; 923 ctx.funcname = symbol; 924 new_argv = traceprobe_expand_meta_args(argc, argv, &new_argc, 925 abuf, MAX_BTF_ARGS_LEN, &ctx); 926 if (IS_ERR(new_argv)) { 927 ret = PTR_ERR(new_argv); 928 new_argv = NULL; 929 goto out; 930 } 931 if (new_argv) { 932 argc = new_argc; 933 argv = new_argv; 934 } 935 936 /* setup a probe */ 937 tk = alloc_trace_kprobe(group, event, addr, symbol, offset, maxactive, 938 argc, is_return); 939 if (IS_ERR(tk)) { 940 ret = PTR_ERR(tk); 941 /* This must return -ENOMEM, else there is a bug */ 942 WARN_ON_ONCE(ret != -ENOMEM); 943 goto out; /* We know tk is not allocated */ 944 } 945 946 /* parse arguments */ 947 for (i = 0; i < argc && i < MAX_TRACE_ARGS; i++) { 948 trace_probe_log_set_index(i + 2); 949 ctx.offset = 0; 950 ret = traceprobe_parse_probe_arg(&tk->tp, i, argv[i], &ctx); 951 if (ret) 952 goto error; /* This can be -ENOMEM */ 953 } 954 /* entry handler for kretprobe */ 955 if (is_return && tk->tp.entry_arg) { 956 tk->rp.entry_handler = trace_kprobe_entry_handler; 957 tk->rp.data_size = traceprobe_get_entry_data_size(&tk->tp); 958 } 959 960 ptype = is_return ? PROBE_PRINT_RETURN : PROBE_PRINT_NORMAL; 961 ret = traceprobe_set_print_fmt(&tk->tp, ptype); 962 if (ret < 0) 963 goto error; 964 965 ret = register_trace_kprobe(tk); 966 if (ret) { 967 trace_probe_log_set_index(1); 968 if (ret == -EILSEQ) 969 trace_probe_log_err(0, BAD_INSN_BNDRY); 970 else if (ret == -ENOENT) 971 trace_probe_log_err(0, BAD_PROBE_ADDR); 972 else if (ret != -ENOMEM && ret != -EEXIST) 973 trace_probe_log_err(0, FAIL_REG_PROBE); 974 goto error; 975 } 976 977out: 978 traceprobe_finish_parse(&ctx); 979 trace_probe_log_clear(); 980 kfree(new_argv); 981 kfree(symbol); 982 return ret; 983 984parse_error: 985 ret = -EINVAL; 986error: 987 free_trace_kprobe(tk); 988 goto out; 989} 990 991static int trace_kprobe_create(const char *raw_command) 992{ 993 return trace_probe_create(raw_command, __trace_kprobe_create); 994} 995 996static int create_or_delete_trace_kprobe(const char *raw_command) 997{ 998 int ret; 999 1000 if (raw_command[0] == '-') 1001 return dyn_event_release(raw_command, &trace_kprobe_ops); 1002 1003 ret = trace_kprobe_create(raw_command); 1004 return ret == -ECANCELED ? -EINVAL : ret; 1005} 1006 1007static int trace_kprobe_run_command(struct dynevent_cmd *cmd) 1008{ 1009 return create_or_delete_trace_kprobe(cmd->seq.buffer); 1010} 1011 1012/** 1013 * kprobe_event_cmd_init - Initialize a kprobe event command object 1014 * @cmd: A pointer to the dynevent_cmd struct representing the new event 1015 * @buf: A pointer to the buffer used to build the command 1016 * @maxlen: The length of the buffer passed in @buf 1017 * 1018 * Initialize a synthetic event command object. Use this before 1019 * calling any of the other kprobe_event functions. 1020 */ 1021void kprobe_event_cmd_init(struct dynevent_cmd *cmd, char *buf, int maxlen) 1022{ 1023 dynevent_cmd_init(cmd, buf, maxlen, DYNEVENT_TYPE_KPROBE, 1024 trace_kprobe_run_command); 1025} 1026EXPORT_SYMBOL_GPL(kprobe_event_cmd_init); 1027 1028/** 1029 * __kprobe_event_gen_cmd_start - Generate a kprobe event command from arg list 1030 * @cmd: A pointer to the dynevent_cmd struct representing the new event 1031 * @kretprobe: Is this a return probe? 1032 * @name: The name of the kprobe event 1033 * @loc: The location of the kprobe event 1034 * @...: Variable number of arg (pairs), one pair for each field 1035 * 1036 * NOTE: Users normally won't want to call this function directly, but 1037 * rather use the kprobe_event_gen_cmd_start() wrapper, which automatically 1038 * adds a NULL to the end of the arg list. If this function is used 1039 * directly, make sure the last arg in the variable arg list is NULL. 1040 * 1041 * Generate a kprobe event command to be executed by 1042 * kprobe_event_gen_cmd_end(). This function can be used to generate the 1043 * complete command or only the first part of it; in the latter case, 1044 * kprobe_event_add_fields() can be used to add more fields following this. 1045 * 1046 * Unlikely the synth_event_gen_cmd_start(), @loc must be specified. This 1047 * returns -EINVAL if @loc == NULL. 1048 * 1049 * Return: 0 if successful, error otherwise. 1050 */ 1051int __kprobe_event_gen_cmd_start(struct dynevent_cmd *cmd, bool kretprobe, 1052 const char *name, const char *loc, ...) 1053{ 1054 char buf[MAX_EVENT_NAME_LEN]; 1055 struct dynevent_arg arg; 1056 va_list args; 1057 int ret; 1058 1059 if (cmd->type != DYNEVENT_TYPE_KPROBE) 1060 return -EINVAL; 1061 1062 if (!loc) 1063 return -EINVAL; 1064 1065 if (kretprobe) 1066 snprintf(buf, MAX_EVENT_NAME_LEN, "r:kprobes/%s", name); 1067 else 1068 snprintf(buf, MAX_EVENT_NAME_LEN, "p:kprobes/%s", name); 1069 1070 ret = dynevent_str_add(cmd, buf); 1071 if (ret) 1072 return ret; 1073 1074 dynevent_arg_init(&arg, 0); 1075 arg.str = loc; 1076 ret = dynevent_arg_add(cmd, &arg, NULL); 1077 if (ret) 1078 return ret; 1079 1080 va_start(args, loc); 1081 for (;;) { 1082 const char *field; 1083 1084 field = va_arg(args, const char *); 1085 if (!field) 1086 break; 1087 1088 if (++cmd->n_fields > MAX_TRACE_ARGS) { 1089 ret = -EINVAL; 1090 break; 1091 } 1092 1093 arg.str = field; 1094 ret = dynevent_arg_add(cmd, &arg, NULL); 1095 if (ret) 1096 break; 1097 } 1098 va_end(args); 1099 1100 return ret; 1101} 1102EXPORT_SYMBOL_GPL(__kprobe_event_gen_cmd_start); 1103 1104/** 1105 * __kprobe_event_add_fields - Add probe fields to a kprobe command from arg list 1106 * @cmd: A pointer to the dynevent_cmd struct representing the new event 1107 * @...: Variable number of arg (pairs), one pair for each field 1108 * 1109 * NOTE: Users normally won't want to call this function directly, but 1110 * rather use the kprobe_event_add_fields() wrapper, which 1111 * automatically adds a NULL to the end of the arg list. If this 1112 * function is used directly, make sure the last arg in the variable 1113 * arg list is NULL. 1114 * 1115 * Add probe fields to an existing kprobe command using a variable 1116 * list of args. Fields are added in the same order they're listed. 1117 * 1118 * Return: 0 if successful, error otherwise. 1119 */ 1120int __kprobe_event_add_fields(struct dynevent_cmd *cmd, ...) 1121{ 1122 struct dynevent_arg arg; 1123 va_list args; 1124 int ret = 0; 1125 1126 if (cmd->type != DYNEVENT_TYPE_KPROBE) 1127 return -EINVAL; 1128 1129 dynevent_arg_init(&arg, 0); 1130 1131 va_start(args, cmd); 1132 for (;;) { 1133 const char *field; 1134 1135 field = va_arg(args, const char *); 1136 if (!field) 1137 break; 1138 1139 if (++cmd->n_fields > MAX_TRACE_ARGS) { 1140 ret = -EINVAL; 1141 break; 1142 } 1143 1144 arg.str = field; 1145 ret = dynevent_arg_add(cmd, &arg, NULL); 1146 if (ret) 1147 break; 1148 } 1149 va_end(args); 1150 1151 return ret; 1152} 1153EXPORT_SYMBOL_GPL(__kprobe_event_add_fields); 1154 1155/** 1156 * kprobe_event_delete - Delete a kprobe event 1157 * @name: The name of the kprobe event to delete 1158 * 1159 * Delete a kprobe event with the give @name from kernel code rather 1160 * than directly from the command line. 1161 * 1162 * Return: 0 if successful, error otherwise. 1163 */ 1164int kprobe_event_delete(const char *name) 1165{ 1166 char buf[MAX_EVENT_NAME_LEN]; 1167 1168 snprintf(buf, MAX_EVENT_NAME_LEN, "-:%s", name); 1169 1170 return create_or_delete_trace_kprobe(buf); 1171} 1172EXPORT_SYMBOL_GPL(kprobe_event_delete); 1173 1174static int trace_kprobe_release(struct dyn_event *ev) 1175{ 1176 struct trace_kprobe *tk = to_trace_kprobe(ev); 1177 int ret = unregister_trace_kprobe(tk); 1178 1179 if (!ret) 1180 free_trace_kprobe(tk); 1181 return ret; 1182} 1183 1184static int trace_kprobe_show(struct seq_file *m, struct dyn_event *ev) 1185{ 1186 struct trace_kprobe *tk = to_trace_kprobe(ev); 1187 int i; 1188 1189 seq_putc(m, trace_kprobe_is_return(tk) ? 'r' : 'p'); 1190 if (trace_kprobe_is_return(tk) && tk->rp.maxactive) 1191 seq_printf(m, "%d", tk->rp.maxactive); 1192 seq_printf(m, ":%s/%s", trace_probe_group_name(&tk->tp), 1193 trace_probe_name(&tk->tp)); 1194 1195 if (!tk->symbol) 1196 seq_printf(m, " 0x%p", tk->rp.kp.addr); 1197 else if (tk->rp.kp.offset) 1198 seq_printf(m, " %s+%u", trace_kprobe_symbol(tk), 1199 tk->rp.kp.offset); 1200 else 1201 seq_printf(m, " %s", trace_kprobe_symbol(tk)); 1202 1203 for (i = 0; i < tk->tp.nr_args; i++) 1204 seq_printf(m, " %s=%s", tk->tp.args[i].name, tk->tp.args[i].comm); 1205 seq_putc(m, '\n'); 1206 1207 return 0; 1208} 1209 1210static int probes_seq_show(struct seq_file *m, void *v) 1211{ 1212 struct dyn_event *ev = v; 1213 1214 if (!is_trace_kprobe(ev)) 1215 return 0; 1216 1217 return trace_kprobe_show(m, ev); 1218} 1219 1220static const struct seq_operations probes_seq_op = { 1221 .start = dyn_event_seq_start, 1222 .next = dyn_event_seq_next, 1223 .stop = dyn_event_seq_stop, 1224 .show = probes_seq_show 1225}; 1226 1227static int probes_open(struct inode *inode, struct file *file) 1228{ 1229 int ret; 1230 1231 ret = security_locked_down(LOCKDOWN_TRACEFS); 1232 if (ret) 1233 return ret; 1234 1235 if ((file->f_mode & FMODE_WRITE) && (file->f_flags & O_TRUNC)) { 1236 ret = dyn_events_release_all(&trace_kprobe_ops); 1237 if (ret < 0) 1238 return ret; 1239 } 1240 1241 return seq_open(file, &probes_seq_op); 1242} 1243 1244static ssize_t probes_write(struct file *file, const char __user *buffer, 1245 size_t count, loff_t *ppos) 1246{ 1247 return trace_parse_run_command(file, buffer, count, ppos, 1248 create_or_delete_trace_kprobe); 1249} 1250 1251static const struct file_operations kprobe_events_ops = { 1252 .owner = THIS_MODULE, 1253 .open = probes_open, 1254 .read = seq_read, 1255 .llseek = seq_lseek, 1256 .release = seq_release, 1257 .write = probes_write, 1258}; 1259 1260static unsigned long trace_kprobe_missed(struct trace_kprobe *tk) 1261{ 1262 return trace_kprobe_is_return(tk) ? 1263 tk->rp.kp.nmissed + tk->rp.nmissed : tk->rp.kp.nmissed; 1264} 1265 1266/* Probes profiling interfaces */ 1267static int probes_profile_seq_show(struct seq_file *m, void *v) 1268{ 1269 struct dyn_event *ev = v; 1270 struct trace_kprobe *tk; 1271 unsigned long nmissed; 1272 1273 if (!is_trace_kprobe(ev)) 1274 return 0; 1275 1276 tk = to_trace_kprobe(ev); 1277 nmissed = trace_kprobe_missed(tk); 1278 seq_printf(m, " %-44s %15lu %15lu\n", 1279 trace_probe_name(&tk->tp), 1280 trace_kprobe_nhit(tk), 1281 nmissed); 1282 1283 return 0; 1284} 1285 1286static const struct seq_operations profile_seq_op = { 1287 .start = dyn_event_seq_start, 1288 .next = dyn_event_seq_next, 1289 .stop = dyn_event_seq_stop, 1290 .show = probes_profile_seq_show 1291}; 1292 1293static int profile_open(struct inode *inode, struct file *file) 1294{ 1295 int ret; 1296 1297 ret = security_locked_down(LOCKDOWN_TRACEFS); 1298 if (ret) 1299 return ret; 1300 1301 return seq_open(file, &profile_seq_op); 1302} 1303 1304static const struct file_operations kprobe_profile_ops = { 1305 .owner = THIS_MODULE, 1306 .open = profile_open, 1307 .read = seq_read, 1308 .llseek = seq_lseek, 1309 .release = seq_release, 1310}; 1311 1312/* Note that we don't verify it, since the code does not come from user space */ 1313static int 1314process_fetch_insn(struct fetch_insn *code, void *rec, void *edata, 1315 void *dest, void *base) 1316{ 1317 struct pt_regs *regs = rec; 1318 unsigned long val; 1319 int ret; 1320 1321retry: 1322 /* 1st stage: get value from context */ 1323 switch (code->op) { 1324 case FETCH_OP_REG: 1325 val = regs_get_register(regs, code->param); 1326 break; 1327 case FETCH_OP_STACK: 1328 val = regs_get_kernel_stack_nth(regs, code->param); 1329 break; 1330 case FETCH_OP_STACKP: 1331 val = kernel_stack_pointer(regs); 1332 break; 1333 case FETCH_OP_RETVAL: 1334 val = regs_return_value(regs); 1335 break; 1336#ifdef CONFIG_HAVE_FUNCTION_ARG_ACCESS_API 1337 case FETCH_OP_ARG: 1338 val = regs_get_kernel_argument(regs, code->param); 1339 break; 1340 case FETCH_OP_EDATA: 1341 val = *(unsigned long *)((unsigned long)edata + code->offset); 1342 break; 1343#endif 1344 case FETCH_NOP_SYMBOL: /* Ignore a place holder */ 1345 code++; 1346 goto retry; 1347 default: 1348 ret = process_common_fetch_insn(code, &val); 1349 if (ret < 0) 1350 return ret; 1351 } 1352 code++; 1353 1354 return process_fetch_insn_bottom(code, val, dest, base); 1355} 1356NOKPROBE_SYMBOL(process_fetch_insn) 1357 1358/* Kprobe handler */ 1359static nokprobe_inline void 1360__kprobe_trace_func(struct trace_kprobe *tk, struct pt_regs *regs, 1361 struct trace_event_file *trace_file) 1362{ 1363 struct kprobe_trace_entry_head *entry; 1364 struct trace_event_call *call = trace_probe_event_call(&tk->tp); 1365 struct trace_event_buffer fbuffer; 1366 int dsize; 1367 1368 WARN_ON(call != trace_file->event_call); 1369 1370 if (trace_trigger_soft_disabled(trace_file)) 1371 return; 1372 1373 dsize = __get_data_size(&tk->tp, regs, NULL); 1374 1375 entry = trace_event_buffer_reserve(&fbuffer, trace_file, 1376 sizeof(*entry) + tk->tp.size + dsize); 1377 if (!entry) 1378 return; 1379 1380 fbuffer.regs = regs; 1381 entry->ip = (unsigned long)tk->rp.kp.addr; 1382 store_trace_args(&entry[1], &tk->tp, regs, NULL, sizeof(*entry), dsize); 1383 1384 trace_event_buffer_commit(&fbuffer); 1385} 1386 1387static void 1388kprobe_trace_func(struct trace_kprobe *tk, struct pt_regs *regs) 1389{ 1390 struct event_file_link *link; 1391 1392 trace_probe_for_each_link_rcu(link, &tk->tp) 1393 __kprobe_trace_func(tk, regs, link->file); 1394} 1395NOKPROBE_SYMBOL(kprobe_trace_func); 1396 1397/* Kretprobe handler */ 1398 1399static int trace_kprobe_entry_handler(struct kretprobe_instance *ri, 1400 struct pt_regs *regs) 1401{ 1402 struct kretprobe *rp = get_kretprobe(ri); 1403 struct trace_kprobe *tk; 1404 1405 /* 1406 * There is a small chance that get_kretprobe(ri) returns NULL when 1407 * the kretprobe is unregister on another CPU between kretprobe's 1408 * trampoline_handler and this function. 1409 */ 1410 if (unlikely(!rp)) 1411 return -ENOENT; 1412 1413 tk = container_of(rp, struct trace_kprobe, rp); 1414 1415 /* store argument values into ri->data as entry data */ 1416 if (tk->tp.entry_arg) 1417 store_trace_entry_data(ri->data, &tk->tp, regs); 1418 1419 return 0; 1420} 1421 1422 1423static nokprobe_inline void 1424__kretprobe_trace_func(struct trace_kprobe *tk, struct kretprobe_instance *ri, 1425 struct pt_regs *regs, 1426 struct trace_event_file *trace_file) 1427{ 1428 struct kretprobe_trace_entry_head *entry; 1429 struct trace_event_buffer fbuffer; 1430 struct trace_event_call *call = trace_probe_event_call(&tk->tp); 1431 int dsize; 1432 1433 WARN_ON(call != trace_file->event_call); 1434 1435 if (trace_trigger_soft_disabled(trace_file)) 1436 return; 1437 1438 dsize = __get_data_size(&tk->tp, regs, ri->data); 1439 1440 entry = trace_event_buffer_reserve(&fbuffer, trace_file, 1441 sizeof(*entry) + tk->tp.size + dsize); 1442 if (!entry) 1443 return; 1444 1445 fbuffer.regs = regs; 1446 entry->func = (unsigned long)tk->rp.kp.addr; 1447 entry->ret_ip = get_kretprobe_retaddr(ri); 1448 store_trace_args(&entry[1], &tk->tp, regs, ri->data, sizeof(*entry), dsize); 1449 1450 trace_event_buffer_commit(&fbuffer); 1451} 1452 1453static void 1454kretprobe_trace_func(struct trace_kprobe *tk, struct kretprobe_instance *ri, 1455 struct pt_regs *regs) 1456{ 1457 struct event_file_link *link; 1458 1459 trace_probe_for_each_link_rcu(link, &tk->tp) 1460 __kretprobe_trace_func(tk, ri, regs, link->file); 1461} 1462NOKPROBE_SYMBOL(kretprobe_trace_func); 1463 1464/* Event entry printers */ 1465static enum print_line_t 1466print_kprobe_event(struct trace_iterator *iter, int flags, 1467 struct trace_event *event) 1468{ 1469 struct kprobe_trace_entry_head *field; 1470 struct trace_seq *s = &iter->seq; 1471 struct trace_probe *tp; 1472 1473 field = (struct kprobe_trace_entry_head *)iter->ent; 1474 tp = trace_probe_primary_from_call( 1475 container_of(event, struct trace_event_call, event)); 1476 if (WARN_ON_ONCE(!tp)) 1477 goto out; 1478 1479 trace_seq_printf(s, "%s: (", trace_probe_name(tp)); 1480 1481 if (!seq_print_ip_sym(s, field->ip, flags | TRACE_ITER_SYM_OFFSET)) 1482 goto out; 1483 1484 trace_seq_putc(s, ')'); 1485 1486 if (trace_probe_print_args(s, tp->args, tp->nr_args, 1487 (u8 *)&field[1], field) < 0) 1488 goto out; 1489 1490 trace_seq_putc(s, '\n'); 1491 out: 1492 return trace_handle_return(s); 1493} 1494 1495static enum print_line_t 1496print_kretprobe_event(struct trace_iterator *iter, int flags, 1497 struct trace_event *event) 1498{ 1499 struct kretprobe_trace_entry_head *field; 1500 struct trace_seq *s = &iter->seq; 1501 struct trace_probe *tp; 1502 1503 field = (struct kretprobe_trace_entry_head *)iter->ent; 1504 tp = trace_probe_primary_from_call( 1505 container_of(event, struct trace_event_call, event)); 1506 if (WARN_ON_ONCE(!tp)) 1507 goto out; 1508 1509 trace_seq_printf(s, "%s: (", trace_probe_name(tp)); 1510 1511 if (!seq_print_ip_sym(s, field->ret_ip, flags | TRACE_ITER_SYM_OFFSET)) 1512 goto out; 1513 1514 trace_seq_puts(s, " <- "); 1515 1516 if (!seq_print_ip_sym(s, field->func, flags & ~TRACE_ITER_SYM_OFFSET)) 1517 goto out; 1518 1519 trace_seq_putc(s, ')'); 1520 1521 if (trace_probe_print_args(s, tp->args, tp->nr_args, 1522 (u8 *)&field[1], field) < 0) 1523 goto out; 1524 1525 trace_seq_putc(s, '\n'); 1526 1527 out: 1528 return trace_handle_return(s); 1529} 1530 1531 1532static int kprobe_event_define_fields(struct trace_event_call *event_call) 1533{ 1534 int ret; 1535 struct kprobe_trace_entry_head field; 1536 struct trace_probe *tp; 1537 1538 tp = trace_probe_primary_from_call(event_call); 1539 if (WARN_ON_ONCE(!tp)) 1540 return -ENOENT; 1541 1542 DEFINE_FIELD(unsigned long, ip, FIELD_STRING_IP, 0); 1543 1544 return traceprobe_define_arg_fields(event_call, sizeof(field), tp); 1545} 1546 1547static int kretprobe_event_define_fields(struct trace_event_call *event_call) 1548{ 1549 int ret; 1550 struct kretprobe_trace_entry_head field; 1551 struct trace_probe *tp; 1552 1553 tp = trace_probe_primary_from_call(event_call); 1554 if (WARN_ON_ONCE(!tp)) 1555 return -ENOENT; 1556 1557 DEFINE_FIELD(unsigned long, func, FIELD_STRING_FUNC, 0); 1558 DEFINE_FIELD(unsigned long, ret_ip, FIELD_STRING_RETIP, 0); 1559 1560 return traceprobe_define_arg_fields(event_call, sizeof(field), tp); 1561} 1562 1563#ifdef CONFIG_PERF_EVENTS 1564 1565/* Kprobe profile handler */ 1566static int 1567kprobe_perf_func(struct trace_kprobe *tk, struct pt_regs *regs) 1568{ 1569 struct trace_event_call *call = trace_probe_event_call(&tk->tp); 1570 struct kprobe_trace_entry_head *entry; 1571 struct hlist_head *head; 1572 int size, __size, dsize; 1573 int rctx; 1574 1575 if (bpf_prog_array_valid(call)) { 1576 unsigned long orig_ip = instruction_pointer(regs); 1577 int ret; 1578 1579 ret = trace_call_bpf(call, regs); 1580 1581 /* 1582 * We need to check and see if we modified the pc of the 1583 * pt_regs, and if so return 1 so that we don't do the 1584 * single stepping. 1585 */ 1586 if (orig_ip != instruction_pointer(regs)) 1587 return 1; 1588 if (!ret) 1589 return 0; 1590 } 1591 1592 head = this_cpu_ptr(call->perf_events); 1593 if (hlist_empty(head)) 1594 return 0; 1595 1596 dsize = __get_data_size(&tk->tp, regs, NULL); 1597 __size = sizeof(*entry) + tk->tp.size + dsize; 1598 size = ALIGN(__size + sizeof(u32), sizeof(u64)); 1599 size -= sizeof(u32); 1600 1601 entry = perf_trace_buf_alloc(size, NULL, &rctx); 1602 if (!entry) 1603 return 0; 1604 1605 entry->ip = (unsigned long)tk->rp.kp.addr; 1606 memset(&entry[1], 0, dsize); 1607 store_trace_args(&entry[1], &tk->tp, regs, NULL, sizeof(*entry), dsize); 1608 perf_trace_buf_submit(entry, size, rctx, call->event.type, 1, regs, 1609 head, NULL); 1610 return 0; 1611} 1612NOKPROBE_SYMBOL(kprobe_perf_func); 1613 1614/* Kretprobe profile handler */ 1615static void 1616kretprobe_perf_func(struct trace_kprobe *tk, struct kretprobe_instance *ri, 1617 struct pt_regs *regs) 1618{ 1619 struct trace_event_call *call = trace_probe_event_call(&tk->tp); 1620 struct kretprobe_trace_entry_head *entry; 1621 struct hlist_head *head; 1622 int size, __size, dsize; 1623 int rctx; 1624 1625 if (bpf_prog_array_valid(call) && !trace_call_bpf(call, regs)) 1626 return; 1627 1628 head = this_cpu_ptr(call->perf_events); 1629 if (hlist_empty(head)) 1630 return; 1631 1632 dsize = __get_data_size(&tk->tp, regs, ri->data); 1633 __size = sizeof(*entry) + tk->tp.size + dsize; 1634 size = ALIGN(__size + sizeof(u32), sizeof(u64)); 1635 size -= sizeof(u32); 1636 1637 entry = perf_trace_buf_alloc(size, NULL, &rctx); 1638 if (!entry) 1639 return; 1640 1641 entry->func = (unsigned long)tk->rp.kp.addr; 1642 entry->ret_ip = get_kretprobe_retaddr(ri); 1643 store_trace_args(&entry[1], &tk->tp, regs, ri->data, sizeof(*entry), dsize); 1644 perf_trace_buf_submit(entry, size, rctx, call->event.type, 1, regs, 1645 head, NULL); 1646} 1647NOKPROBE_SYMBOL(kretprobe_perf_func); 1648 1649int bpf_get_kprobe_info(const struct perf_event *event, u32 *fd_type, 1650 const char **symbol, u64 *probe_offset, 1651 u64 *probe_addr, unsigned long *missed, 1652 bool perf_type_tracepoint) 1653{ 1654 const char *pevent = trace_event_name(event->tp_event); 1655 const char *group = event->tp_event->class->system; 1656 struct trace_kprobe *tk; 1657 1658 if (perf_type_tracepoint) 1659 tk = find_trace_kprobe(pevent, group); 1660 else 1661 tk = trace_kprobe_primary_from_call(event->tp_event); 1662 if (!tk) 1663 return -EINVAL; 1664 1665 *fd_type = trace_kprobe_is_return(tk) ? BPF_FD_TYPE_KRETPROBE 1666 : BPF_FD_TYPE_KPROBE; 1667 *probe_offset = tk->rp.kp.offset; 1668 *probe_addr = kallsyms_show_value(current_cred()) ? 1669 (unsigned long)tk->rp.kp.addr : 0; 1670 *symbol = tk->symbol; 1671 if (missed) 1672 *missed = trace_kprobe_missed(tk); 1673 return 0; 1674} 1675#endif /* CONFIG_PERF_EVENTS */ 1676 1677/* 1678 * called by perf_trace_init() or __ftrace_set_clr_event() under event_mutex. 1679 * 1680 * kprobe_trace_self_tests_init() does enable_trace_probe/disable_trace_probe 1681 * lockless, but we can't race with this __init function. 1682 */ 1683static int kprobe_register(struct trace_event_call *event, 1684 enum trace_reg type, void *data) 1685{ 1686 struct trace_event_file *file = data; 1687 1688 switch (type) { 1689 case TRACE_REG_REGISTER: 1690 return enable_trace_kprobe(event, file); 1691 case TRACE_REG_UNREGISTER: 1692 return disable_trace_kprobe(event, file); 1693 1694#ifdef CONFIG_PERF_EVENTS 1695 case TRACE_REG_PERF_REGISTER: 1696 return enable_trace_kprobe(event, NULL); 1697 case TRACE_REG_PERF_UNREGISTER: 1698 return disable_trace_kprobe(event, NULL); 1699 case TRACE_REG_PERF_OPEN: 1700 case TRACE_REG_PERF_CLOSE: 1701 case TRACE_REG_PERF_ADD: 1702 case TRACE_REG_PERF_DEL: 1703 return 0; 1704#endif 1705 } 1706 return 0; 1707} 1708 1709static int kprobe_dispatcher(struct kprobe *kp, struct pt_regs *regs) 1710{ 1711 struct trace_kprobe *tk = container_of(kp, struct trace_kprobe, rp.kp); 1712 int ret = 0; 1713 1714 raw_cpu_inc(*tk->nhit); 1715 1716 if (trace_probe_test_flag(&tk->tp, TP_FLAG_TRACE)) 1717 kprobe_trace_func(tk, regs); 1718#ifdef CONFIG_PERF_EVENTS 1719 if (trace_probe_test_flag(&tk->tp, TP_FLAG_PROFILE)) 1720 ret = kprobe_perf_func(tk, regs); 1721#endif 1722 return ret; 1723} 1724NOKPROBE_SYMBOL(kprobe_dispatcher); 1725 1726static int 1727kretprobe_dispatcher(struct kretprobe_instance *ri, struct pt_regs *regs) 1728{ 1729 struct kretprobe *rp = get_kretprobe(ri); 1730 struct trace_kprobe *tk; 1731 1732 /* 1733 * There is a small chance that get_kretprobe(ri) returns NULL when 1734 * the kretprobe is unregister on another CPU between kretprobe's 1735 * trampoline_handler and this function. 1736 */ 1737 if (unlikely(!rp)) 1738 return 0; 1739 1740 tk = container_of(rp, struct trace_kprobe, rp); 1741 raw_cpu_inc(*tk->nhit); 1742 1743 if (trace_probe_test_flag(&tk->tp, TP_FLAG_TRACE)) 1744 kretprobe_trace_func(tk, ri, regs); 1745#ifdef CONFIG_PERF_EVENTS 1746 if (trace_probe_test_flag(&tk->tp, TP_FLAG_PROFILE)) 1747 kretprobe_perf_func(tk, ri, regs); 1748#endif 1749 return 0; /* We don't tweak kernel, so just return 0 */ 1750} 1751NOKPROBE_SYMBOL(kretprobe_dispatcher); 1752 1753static struct trace_event_functions kretprobe_funcs = { 1754 .trace = print_kretprobe_event 1755}; 1756 1757static struct trace_event_functions kprobe_funcs = { 1758 .trace = print_kprobe_event 1759}; 1760 1761static struct trace_event_fields kretprobe_fields_array[] = { 1762 { .type = TRACE_FUNCTION_TYPE, 1763 .define_fields = kretprobe_event_define_fields }, 1764 {} 1765}; 1766 1767static struct trace_event_fields kprobe_fields_array[] = { 1768 { .type = TRACE_FUNCTION_TYPE, 1769 .define_fields = kprobe_event_define_fields }, 1770 {} 1771}; 1772 1773static inline void init_trace_event_call(struct trace_kprobe *tk) 1774{ 1775 struct trace_event_call *call = trace_probe_event_call(&tk->tp); 1776 1777 if (trace_kprobe_is_return(tk)) { 1778 call->event.funcs = &kretprobe_funcs; 1779 call->class->fields_array = kretprobe_fields_array; 1780 } else { 1781 call->event.funcs = &kprobe_funcs; 1782 call->class->fields_array = kprobe_fields_array; 1783 } 1784 1785 call->flags = TRACE_EVENT_FL_KPROBE; 1786 call->class->reg = kprobe_register; 1787} 1788 1789static int register_kprobe_event(struct trace_kprobe *tk) 1790{ 1791 init_trace_event_call(tk); 1792 1793 return trace_probe_register_event_call(&tk->tp); 1794} 1795 1796static int unregister_kprobe_event(struct trace_kprobe *tk) 1797{ 1798 return trace_probe_unregister_event_call(&tk->tp); 1799} 1800 1801#ifdef CONFIG_PERF_EVENTS 1802 1803/* create a trace_kprobe, but don't add it to global lists */ 1804struct trace_event_call * 1805create_local_trace_kprobe(char *func, void *addr, unsigned long offs, 1806 bool is_return) 1807{ 1808 enum probe_print_type ptype; 1809 struct trace_kprobe *tk; 1810 int ret; 1811 char *event; 1812 1813 if (func) { 1814 unsigned int count; 1815 1816 count = number_of_same_symbols(func); 1817 if (count > 1) 1818 /* 1819 * Users should use addr to remove the ambiguity of 1820 * using func only. 1821 */ 1822 return ERR_PTR(-EADDRNOTAVAIL); 1823 else if (count == 0) 1824 /* 1825 * We can return ENOENT earlier than when register the 1826 * kprobe. 1827 */ 1828 return ERR_PTR(-ENOENT); 1829 } 1830 1831 /* 1832 * local trace_kprobes are not added to dyn_event, so they are never 1833 * searched in find_trace_kprobe(). Therefore, there is no concern of 1834 * duplicated name here. 1835 */ 1836 event = func ? func : "DUMMY_EVENT"; 1837 1838 tk = alloc_trace_kprobe(KPROBE_EVENT_SYSTEM, event, (void *)addr, func, 1839 offs, 0 /* maxactive */, 0 /* nargs */, 1840 is_return); 1841 1842 if (IS_ERR(tk)) { 1843 pr_info("Failed to allocate trace_probe.(%d)\n", 1844 (int)PTR_ERR(tk)); 1845 return ERR_CAST(tk); 1846 } 1847 1848 init_trace_event_call(tk); 1849 1850 ptype = trace_kprobe_is_return(tk) ? 1851 PROBE_PRINT_RETURN : PROBE_PRINT_NORMAL; 1852 if (traceprobe_set_print_fmt(&tk->tp, ptype) < 0) { 1853 ret = -ENOMEM; 1854 goto error; 1855 } 1856 1857 ret = __register_trace_kprobe(tk); 1858 if (ret < 0) 1859 goto error; 1860 1861 return trace_probe_event_call(&tk->tp); 1862error: 1863 free_trace_kprobe(tk); 1864 return ERR_PTR(ret); 1865} 1866 1867void destroy_local_trace_kprobe(struct trace_event_call *event_call) 1868{ 1869 struct trace_kprobe *tk; 1870 1871 tk = trace_kprobe_primary_from_call(event_call); 1872 if (unlikely(!tk)) 1873 return; 1874 1875 if (trace_probe_is_enabled(&tk->tp)) { 1876 WARN_ON(1); 1877 return; 1878 } 1879 1880 __unregister_trace_kprobe(tk); 1881 1882 free_trace_kprobe(tk); 1883} 1884#endif /* CONFIG_PERF_EVENTS */ 1885 1886static __init void enable_boot_kprobe_events(void) 1887{ 1888 struct trace_array *tr = top_trace_array(); 1889 struct trace_event_file *file; 1890 struct trace_kprobe *tk; 1891 struct dyn_event *pos; 1892 1893 mutex_lock(&event_mutex); 1894 for_each_trace_kprobe(tk, pos) { 1895 list_for_each_entry(file, &tr->events, list) 1896 if (file->event_call == trace_probe_event_call(&tk->tp)) 1897 trace_event_enable_disable(file, 1, 0); 1898 } 1899 mutex_unlock(&event_mutex); 1900} 1901 1902static __init void setup_boot_kprobe_events(void) 1903{ 1904 char *p, *cmd = kprobe_boot_events_buf; 1905 int ret; 1906 1907 strreplace(kprobe_boot_events_buf, ',', ' '); 1908 1909 while (cmd && *cmd != '\0') { 1910 p = strchr(cmd, ';'); 1911 if (p) 1912 *p++ = '\0'; 1913 1914 ret = create_or_delete_trace_kprobe(cmd); 1915 if (ret) 1916 pr_warn("Failed to add event(%d): %s\n", ret, cmd); 1917 1918 cmd = p; 1919 } 1920 1921 enable_boot_kprobe_events(); 1922} 1923 1924/* 1925 * Register dynevent at core_initcall. This allows kernel to setup kprobe 1926 * events in postcore_initcall without tracefs. 1927 */ 1928static __init int init_kprobe_trace_early(void) 1929{ 1930 int ret; 1931 1932 ret = dyn_event_register(&trace_kprobe_ops); 1933 if (ret) 1934 return ret; 1935 1936 if (register_module_notifier(&trace_kprobe_module_nb)) 1937 return -EINVAL; 1938 1939 return 0; 1940} 1941core_initcall(init_kprobe_trace_early); 1942 1943/* Make a tracefs interface for controlling probe points */ 1944static __init int init_kprobe_trace(void) 1945{ 1946 int ret; 1947 1948 ret = tracing_init_dentry(); 1949 if (ret) 1950 return 0; 1951 1952 /* Event list interface */ 1953 trace_create_file("kprobe_events", TRACE_MODE_WRITE, 1954 NULL, NULL, &kprobe_events_ops); 1955 1956 /* Profile interface */ 1957 trace_create_file("kprobe_profile", TRACE_MODE_READ, 1958 NULL, NULL, &kprobe_profile_ops); 1959 1960 setup_boot_kprobe_events(); 1961 1962 return 0; 1963} 1964fs_initcall(init_kprobe_trace); 1965 1966 1967#ifdef CONFIG_FTRACE_STARTUP_TEST 1968static __init struct trace_event_file * 1969find_trace_probe_file(struct trace_kprobe *tk, struct trace_array *tr) 1970{ 1971 struct trace_event_file *file; 1972 1973 list_for_each_entry(file, &tr->events, list) 1974 if (file->event_call == trace_probe_event_call(&tk->tp)) 1975 return file; 1976 1977 return NULL; 1978} 1979 1980/* 1981 * Nobody but us can call enable_trace_kprobe/disable_trace_kprobe at this 1982 * stage, we can do this lockless. 1983 */ 1984static __init int kprobe_trace_self_tests_init(void) 1985{ 1986 int ret, warn = 0; 1987 int (*target)(int, int, int, int, int, int); 1988 struct trace_kprobe *tk; 1989 struct trace_event_file *file; 1990 1991 if (tracing_is_disabled()) 1992 return -ENODEV; 1993 1994 if (tracing_selftest_disabled) 1995 return 0; 1996 1997 target = kprobe_trace_selftest_target; 1998 1999 pr_info("Testing kprobe tracing: "); 2000 2001 ret = create_or_delete_trace_kprobe("p:testprobe kprobe_trace_selftest_target $stack $stack0 +0($stack)"); 2002 if (WARN_ON_ONCE(ret)) { 2003 pr_warn("error on probing function entry.\n"); 2004 warn++; 2005 } else { 2006 /* Enable trace point */ 2007 tk = find_trace_kprobe("testprobe", KPROBE_EVENT_SYSTEM); 2008 if (WARN_ON_ONCE(tk == NULL)) { 2009 pr_warn("error on getting new probe.\n"); 2010 warn++; 2011 } else { 2012 file = find_trace_probe_file(tk, top_trace_array()); 2013 if (WARN_ON_ONCE(file == NULL)) { 2014 pr_warn("error on getting probe file.\n"); 2015 warn++; 2016 } else 2017 enable_trace_kprobe( 2018 trace_probe_event_call(&tk->tp), file); 2019 } 2020 } 2021 2022 ret = create_or_delete_trace_kprobe("r:testprobe2 kprobe_trace_selftest_target $retval"); 2023 if (WARN_ON_ONCE(ret)) { 2024 pr_warn("error on probing function return.\n"); 2025 warn++; 2026 } else { 2027 /* Enable trace point */ 2028 tk = find_trace_kprobe("testprobe2", KPROBE_EVENT_SYSTEM); 2029 if (WARN_ON_ONCE(tk == NULL)) { 2030 pr_warn("error on getting 2nd new probe.\n"); 2031 warn++; 2032 } else { 2033 file = find_trace_probe_file(tk, top_trace_array()); 2034 if (WARN_ON_ONCE(file == NULL)) { 2035 pr_warn("error on getting probe file.\n"); 2036 warn++; 2037 } else 2038 enable_trace_kprobe( 2039 trace_probe_event_call(&tk->tp), file); 2040 } 2041 } 2042 2043 if (warn) 2044 goto end; 2045 2046 ret = target(1, 2, 3, 4, 5, 6); 2047 2048 /* 2049 * Not expecting an error here, the check is only to prevent the 2050 * optimizer from removing the call to target() as otherwise there 2051 * are no side-effects and the call is never performed. 2052 */ 2053 if (ret != 21) 2054 warn++; 2055 2056 /* Disable trace points before removing it */ 2057 tk = find_trace_kprobe("testprobe", KPROBE_EVENT_SYSTEM); 2058 if (WARN_ON_ONCE(tk == NULL)) { 2059 pr_warn("error on getting test probe.\n"); 2060 warn++; 2061 } else { 2062 if (trace_kprobe_nhit(tk) != 1) { 2063 pr_warn("incorrect number of testprobe hits\n"); 2064 warn++; 2065 } 2066 2067 file = find_trace_probe_file(tk, top_trace_array()); 2068 if (WARN_ON_ONCE(file == NULL)) { 2069 pr_warn("error on getting probe file.\n"); 2070 warn++; 2071 } else 2072 disable_trace_kprobe( 2073 trace_probe_event_call(&tk->tp), file); 2074 } 2075 2076 tk = find_trace_kprobe("testprobe2", KPROBE_EVENT_SYSTEM); 2077 if (WARN_ON_ONCE(tk == NULL)) { 2078 pr_warn("error on getting 2nd test probe.\n"); 2079 warn++; 2080 } else { 2081 if (trace_kprobe_nhit(tk) != 1) { 2082 pr_warn("incorrect number of testprobe2 hits\n"); 2083 warn++; 2084 } 2085 2086 file = find_trace_probe_file(tk, top_trace_array()); 2087 if (WARN_ON_ONCE(file == NULL)) { 2088 pr_warn("error on getting probe file.\n"); 2089 warn++; 2090 } else 2091 disable_trace_kprobe( 2092 trace_probe_event_call(&tk->tp), file); 2093 } 2094 2095 ret = create_or_delete_trace_kprobe("-:testprobe"); 2096 if (WARN_ON_ONCE(ret)) { 2097 pr_warn("error on deleting a probe.\n"); 2098 warn++; 2099 } 2100 2101 ret = create_or_delete_trace_kprobe("-:testprobe2"); 2102 if (WARN_ON_ONCE(ret)) { 2103 pr_warn("error on deleting a probe.\n"); 2104 warn++; 2105 } 2106 2107end: 2108 ret = dyn_events_release_all(&trace_kprobe_ops); 2109 if (WARN_ON_ONCE(ret)) { 2110 pr_warn("error on cleaning up probes.\n"); 2111 warn++; 2112 } 2113 /* 2114 * Wait for the optimizer work to finish. Otherwise it might fiddle 2115 * with probes in already freed __init text. 2116 */ 2117 wait_for_kprobe_optimizer(); 2118 if (warn) 2119 pr_cont("NG: Some tests are failed. Please check them.\n"); 2120 else 2121 pr_cont("OK\n"); 2122 return 0; 2123} 2124 2125late_initcall(kprobe_trace_self_tests_init); 2126 2127#endif 2128